minor research, major discovery. apparently, not all was done through woodcuts, which represented a durable way to make picture after picture after picture. instead, in the timeless showdown between quality and quantity, pictures like the Melancolia and other, more sculptural images were engraved on copper plates. The copper plate could only make a dozen or so prints (which explains why i was not handed a copper plate in the conservation room of the gallery 10 years ago), but the softness of the metal allowed the detail and texture Durer presents. compare: 
This picture, from Hartmann Schedel’s Chronicle of Nuremberg (1493) is not too much older than Durer’s Melencolia I (1514), and the two are especially interesting to compare since Durer was from Nuremberg as well. But essentially, the 1493 picture is so much more medieval, lacking not only the sculptural depth of Durer’s later copper plate engraving, but displaying a common medieval convention of representing human beings as parts and types (note all the heads crowded together–where are their bodies?). This isn’t to say that Melencolia isn’t a type as well; much scholarship before, after, and including Panofsky has made much of the symbolic language contained within this picture, a very medieval sort of custom which continued strong into the Renaissance, with books of emblems that had specific meanings from “geometry” to “abstract thought.” And certainly the person in Durer’s picture is not a real person, but at most specific the diety Melecolia, a daughter of Cronus who was called Sloth prior to the Renaissance (! Well, it’s true that depressives don’t have much get-up-and-go.) To the modern eye, though, the woodcut of the Jews of Nuremberg looks ancient, and removed from reality, and we’re not surprised if it was not modeled from life. But Durer somehow looks modern, as lifelike as a carved copper plate can be, brimming with knowledge about mathematics and technology and modernity. One of the things I’m endlessly entertained by in art history is that every era’s historians after 1200 or so claim that the art they study represents the birth of the modern. But I think Durer is right on the cusp. I wonder if he would have been as dexterous with pixels.